The principal aim of the research program set forth in this application is to obtain structural information about reactive intermediates in organic chemical reactions. These structural results are invaluable for the development of new synthetic methodology. I particular, the stereoselectivity of common organic reactions is of utmost concern and importance in the design of chemical syntheses of every small organic molecule that is listed in publications such as the NCI publication Chemical Structures of Interest to the Division of Cancer Treatment. The structural information obtained in this research program will permit the rational design of new synthetic reactions and will also yield improved efficiency in organic synthesis. Since a stated goal of the NIH is to obtain chemical compounds for screening as well as for utilization in clinical trails, and since a large number of compounds on the current list of compounds used in clinical trials and in earlier stages of development by the NIH are prepared by organic chemical synthesis, it is extremely important that efficient and useful processes exist for the preparation of such compounds. The research proposed herein will greatly assist with the ongoing development of synthetic organic chemistry leading to the synthesis of physiologically active, small organic molecules. the efficiency of total syntheses of both naturally occurring and non-naturally occurring analogs of such compounds will be improved thorough understanding of the intimate structural details of the reactive intermediates involved in the synthesis of such compounds. Synthetic methodology will be proposed and developed as a consequence of the structural results. The structural results will be obtained by utilizing the techniques of NMR spectroscopy, x-ray diffraction analysis and computional chemistry. The structural results generally are presented as three dimensional representations of aggregated species formed as reactive intermediates is almost all synthetic reactions involving carbanions. This structural information will be utilized to design models to explain and to predict the stereospecificity of organic chemical reactions. Additionally, the structural information will be utilized to develop and to improve new synthetic reagents for the asymmetric synthesis of physiologically active organic molecules. Hence, the structural work will be accompanied by experimental work on the development of new asymmetric reactions for use in the total synthesis of physiologically active compounds.